xlvi 



having a different arrangement of their constituent atoms, the 

 arrangement in each case being dissymmetric, and clearly indicated 

 that whatever the dissymmetry of the one tartaric acid might consist 

 in, it must be related to the dissymmetry of the other tartaric acid 

 in the same sort of way as the dissymmetry of the left hand is 

 related to the dissymmetry of the right hand. At the time, how- 

 over, organic chemistry was not sufficiently advanced to make any 

 immediate use of these speculations, but the philosophical reflections 

 in which he indulges show how, so long ago, he had completely fore- 

 shadowed and grasped the scope of that important branch of chemical 

 science now known as Stereochemistry. 



But if we are impressed with the sagacity and suggestiveness of 

 Pasteur's theoretical speculations, we are filled with even still greater 

 admiration on again turning to his experimental work. The field of 

 investigation which he exposed to view by his discovery of the rela- 

 tionship between the racemic and tartaric acids appears as limitless 

 as the prairie which is bounded only by the horizon, and nothing can 

 testify more eloquently to the experimental genius of Pasteur than 

 the circumstance that already during the comparatively short period 

 of time in which he himself was pursuing its cultivation, he suc- 

 ceeded in determining the exact methods by means of which it can 

 be exploited. ISTo new methods have been devised, no substantial 

 modifications or improvements have been introduced, although many 

 hands of divers nationalities have since been busily engaged in til- 

 ling the estate which he himself was constrained to abandon now 

 nearly thirty years ago. 



Pasteur's academic career was now assured, and the close of the 

 year 1848 finds him Professor of Physics at the Lycee of Dijon, 

 whilst three months after his installation there he was nominated 

 Deputy Professor of Chemistry at the University of Strassburg, 

 becoming full professor in 1852. His removal to Strassburg had 

 another significance, quite apart from the greater scope which it 

 afforded him for carrying on his scientific work, for here he met his 

 future wife, the daughter of M. Laurent, Hector of the Strassburg 

 Academy. Their marriage, which took place in 1860, was a singu- 

 larly happy one, for Madame Pasteur, as Dr. Roux has said, became 

 not only "une compagne incomparable," but Pasteur's " meilleur 

 collaborateur." 



During the five years he resided in Alsace, Pasteur devoted him- 

 self almost exclusively to the systematic investigation of asymmetric 

 compounds. Associated with this period of his life we find those 

 important and now classical researches on the conversion of right- 

 handed tartaric acid into inactive tartaric acid (racemic acid) on the 

 one hand, and into a new form of inactive tartaric acid (mesotartaric 

 acid) on the other, bis discovery of the method of splitting up 



